Apparatus for shredding molten mineral materials into fibers



g- 1967 v H. SCHACHTER I APPARATUS FOR SHREDDING MOLTEN MINERAL I v MATERIALS INTO FIBERS Filed Dec. 1966 United States Patent 3,336,125 APPARATUS FOR SHREDDING MOLTEN MIN- ERAL MATERIALS INTO FIBERS Hairn Schachter, 15 Eilat St., Givatayim, Israel Filed Dec. 6, 1966, Ser. No. 599,520 Claims priority, applicatizon Israel, Nov. 25, 1962,

18, 4 Claims. (CI. 65-14) ABSTRACT OF THE DISCLOSURE This application is a continuation-in-part of my prior application No. 325,540 filed Nov. 22, 1963, now abandoned.

This invention relates to the production of mineral wool using as raw material, minerals such as, for example, rock, slag or glass. The raw material, in lump form, is rendered molten in appropriate melting equipment such as, for example in cupolas and the object is then to shred a stream of the molten material into fibrous form which can then be treated by the addition of organic substances so as to obtain uniform coverage of fibres. The fibrous wool thus obtained accumulates on a conveyor from which a continuous ribbon or blanket of wool can be removed.

According to some hitherto known processes the stream of molten materials is shredded into fibrous form by the action of high pressure steam jets, the molten stream of slag falling onto a splitter, i.e. an angle iron trough which divides the main stream into two or more small streams each of which is hit with a steam blast. It has been found in practice, however, that this method is not effective in producing uniform fine fibres and that the wool produced contains a high proportion of shot, i.e. solid particles of slag which have not been converted into fibres.

In accordance with another known process the use of steam blasts for shredding the molten stream is dispensed with and, in its place, the molten stream is directed onto the surface of a spinning disc or rotor which rotates about a vertical axis, the stream separating into particles which are flung away from the disc under the centrifugal forces obtaining and being thereby converted into fibres. With this method, long fibres of fine diameter can be obtained which are randomly distributed around the rotor. Such long fibres are disadvantageous for use in forming insulating blankets or the like because they militate against a random orientation of the fibres and hence reduce considerably the amount of air trapped between the fibres. Furthermore, the fact that the fibres are uniformly distributed around the rotating disc, demands an extra operation in collecting and coating the fibres with the necessary organic binding substances.

It is an object of the present invention to provide an apparatus and process for the production of mineral wool in which the above referred to disadvantages are substantially reduced.

The invention resides in the directing of a stream of molten mineral material onto the periphery of a rotor which is rotated about a substantially horizontal axis thereby causing the thinning out of said stream and its projection under centrifugal forces away from the rotor, and the directing of a blast of heated gas onto the centrifugally projected stream in a direction transverse thereice to, whereby the stream is shredded into fibres which are projected into a collecting chamber.

An example of apparatus for the production of mineral wool in accordance with the present invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a schematic partially sectioned elevation of apparatus in accordance with the invention, and

FIGS. 2, 3 and 4 are front elevations of respectively gilifGeriirg forms of components of the apparatus shown in As seen in FIG. 1 of the drawings, the apparatus comprises a rotor 1 which is mounted on a horizontal axle 2 arranged to be driven by means not shown. The rotor is so mounted that its peripheral edge 3 is directly below an opening 4 formed in a slag furnace 5. The rotor 1 is surrounded by an annular conduit 6 provided with apertures 7 through which is passed, under pressure, steam.

As seen clearly in FIGS. 2 to 4 of the drawings, the apertures 7 extend along an arc of a circle forming the major portion of the periphery of the circle, the remaining portion 11 of the circle being unapertured. The annular conduit 6 is so disposed with respect to the opening 4 of the slag furnace 5 that the unapertured portion 11 is disposed directly below this opening 4. The rotor 1 faces an opening 8 in a blow chamber 9 in which is provided a driven conveyor belt 10.

In operation, a stream of molten slag falls onto the peripheral edge 3 of the rotor 1 past the unapertured portion 11 of the conduit 6 and is spread out around this edge as a result of the rotation of the rotor. This spread out stream is subjected to a strong blast of steam which is directed transversely to the centrifugal forces acting on the stream and projects the individual droplets of the stream towards the blow chamber. In the course of this projection the droplets become elongated into fibres and the fibres collect on the conveyor belt where they can be suitably coated with any required material and removed.

As seen in FIGS. 2 to 4 of the drawings the outlet apertures of the conduit can have differing forms. Thus as seen in FIG. 2 the outlet aperture 7a can consist of a single elongated arcuate slit. Alternatively as seen in FIG. 3, the outlet apertures 7b may consist of a simple set of holes whilst as seen in FIG. 4 the outlet apertures 70 may be V-shaped. In all cases, however, the portion 11 of the annular conduit is left unapertured and it is adjacent this portion that the molten slag impinges on the peripheral edge of the rotor. Additionally the apertures 7 are disposed substantially coaxially with the rotor 1.

It has been found that the process in accordance with the invention and the apparatus described above for carrying it out, is particularly effective in the production of fine, substantially uniform mineral fibres. Furthermore, the process is particularly useful in the case of relatively small-scale production of fibres. It will be understood that under the conditions prevailing in small-scale production the original stream of molten minerals is relatively small and is therefore liable to cool down so quickly as to prevent its effective conversion into fibres. The process and apparatus described above facilitate the production of the fibres before the stream has had an opportunity to cool down. i

In one particular embodiment of apparatus as shown in the drawings, the temperature of the molten stream emerging from the slag furnace was 1450 C., the pressure of the steam blast was 8 atmospheres whilst the rotor was rotated at a speed of 2000 revolutions per minute.

I claim:

1. Apparatus for the production of mineral wool comprising a generally cylindrical rotor having an outer cylindrical peripheral surface, the axial extent of which is defined by two marginal ends,

means to rotate said rotor about a substantially horizontal axis, means to feed molten mineral downwardly onto said outer cylindrical peripheral surface of said rotor on which the molten mineral is thinned out, and means to blast hot gas in a direction axial to said rotor and transverse to the feed of molten mineral to contact the molten mineral centrifugally projected from said rotor to shred said molten mineral into fibres, said means to blast hot gas comprising a generally annular apertured conduit around said rotor and disposed slightly rearwardly of the front of said two marginal ends. ,2. Apparatus in accordance with claim 1 wherein said annular conduit has a plurality of outlet apertures arranged substantially coaxially with said rotor.

3. Apparatus in accordance with claim 2 wherein said outlet apertures are generally V-shaped.

4. Apparatus in accordance with claim 1 wherein said annular conduit comprises walls defining an elongated arcuate slit-like outlet aperture substantially coaxial with said rotor.

References Cited UNITED STATES PATENTS 2,689,373 9/1954 Richardson 6514 2,882,552 4/1959 Downey 65--l4 3,013,299 12/1961 Owens 65-l4 DONALL H. SYLVESTER, Primary Examiner.

R. L. LINDSAY, Assistant Examiner. 

1. APPARATUS FOR THE PRODUCTION OF MINERAL WOOL COMPRISING A GENERALLY CYLINDRICAL ROTOR HAVING AN OUTER CYLINDRICAL PERIPHERAL SURFACE, THE AXIAL EXTENT OF WHICH IS DEFINED BY TWO MARGINAL ENDS, MEANS TO ROTATE SAID ROTOR ABOUT A SUBSTANTIALLY HORIZONTAL AXIS, MEANS TO FEED MOLTEN MINERAL DOWNWARDLY ONTO SAID OUTER CYLINDRICAL PERIPHERAL SURFACE OF SAID ROTOR ON WHICH THE MOLTEN MINERAL IS THINNED OUT, AND MEANS TO BLAST HOT GAS IN A DIRECTION AXIAL TO SAID ROTOR AND TRANSVERSE TO THE FEED OF MOLTEN MINERAL TO CONTACT THE MOLTEN MINERAL CENTRIFUGALLY PROJECTED FROM SAID ROTOR TO SHRED SAID MOLTEN MINERAL INTO FIBRES, SAID MEANS TO BLAST HOT GAS COMPRISING A GENERALLY ANNULAR APERTURED CONDUIT AROUND SAID ROTOR AND DISPOSED SLIGHTLY REARWARDLY OF THE FRONT OF SAID TWO MARGINAL ENDS. 